Keyboard mechanism for typographical machines



D. S. KENNEDY. KEYBOARD MECHANISM FOR TYPOGRAPHICAL MACHINES.

APPLICATION FILED JUNE 28, I920.

ATTORNEYS.

R M LC Patented Nov. 22, 1921.

D. S. KENNEDY. KEYBOARD MECHANISM FOR TYPOGRAPHICAL MACHINES.

APPLICATION FILED JUNEZB, 1920.

Patented Nov. 22, 1921.

2 SHEETS-SHEET 2.

Eg s.

UNITED STATES P TENT OFFICE.

DAVID S. KENNEDY, 0F BROOKLYN, NEW YORK, ASSIGNOR T0 MERGENTHALER LINOTYPE COMPANY, A CORPORATION OF NEXV YORK.

KEYBOARD MECHANISM FOR Application filed June 28,

To all 1117mmiz' may concern:

Be it known that 1, DAVID S. Knnxnor, a citizen of the United States, residing at Brooklyn, in the county of Kings and titate of New York, have invented certain new and useful Improvements in a Keyboard Mechanism for Typographiczl Machines, of which the following is a specification, reference being had therein to the accompanying drawing. 1

lvlv invention relates to typograpnical machines, such as linotypc machines ot the eneral organization represented in Letters Tatent of States to O. Morgenthe United I thaler No. wherein circulating iomififii, matrices are released from a magazine in the order in which their characters are to appear in print and then assembled in line, the composed line t 'ansterred tothe tare of a slotted mold, the mold filled with molten metal to form a slug or linotype against the matrices which produce the type characters thereon, and 'the matrices thereafter returned through a distributing mechanism to the magazine from which they started. More particularly, it relates LO a machine of the kind covered by my copending application Serial No.

and contemplates certain improvements in the keyboard mechanism employed in said machine, as will be fully set forth in the detailed description to follow.

Referring to the drawings:

Figure l is a side elevation ot the keyboard mechanism of a linotype machine, with certain parts broken away, having my improvements embodied therein;

Fig. :2 is a similar view showing the parts in different position; and

Fig. 3 is a plan view of the parts shown in Fig. 2 but broken away in the center.

I have herein illustrated only those parts of the machine concerned directly with the present invention, reference being made to my co-pending application above mentioned for any ifurthe details or information; and in the following description, the time reference characters are made use of as far as possible so that the corresponding parts may be readily identified.

Pieteri' g to 1. the matrix releasing escapem-cnrs (not shown) are actuated by the reeds E which in turn are operated by the vokes E arranged in banks and provided with the cams or eccentrics E adapted un- Spccification of Letters Patent.

TYPOGRAPHICAL MACHINES.

Patented Nov. 22, 1921.

1920. Serial No. 392,159.

der the influence of the trip dogs or triggers to cooperate with the underlying powerdriven rolls E. The triggers E are controlled from the finger-keys E through interposed mechanism comprising the two series of actuating slides E E and the series of U-shaped rocking bails E The bails E are mounted in groups in the fixed box-like structure J upon the transverse rods J and have their arms extended forwardly through the slotted front wall J to make engagement with the actuating slides. hese actuating slides, on the other hand, are mounted in the adjustable supporting frame H, which is arranged in the machine frame so as to be shift-able longitudinally in opposite directions to locate the slides of either series in engaging relation to the finger keys E, the slides being formed in their forward edges with the notches 0 wherein the rear ends of the linger keys are adapted to engage. W'hen the finger keys E are engaged with the longer or active slides E the latter are disconnected from the bails E and hence establish a series of direct connections between the keys and the trip dogs E; whereas when the finger keys are engaged with the short or tree slides E the latter are connected by the balls E to certain selected longer or active slides E thus establishing a series of offset or indirect connections be tween the keys and the trip dogs E Consequently, by shifting the frame H to the rightor left, the keyboard connections may be adjusted to transfer the control of the finger keys to one or another set of escapement actuating reeds as desired. The shifting of the frame H is effected by means of the forwardly and backwardly movable hand-lever H pivoted at H to the supporting l, ra'cket H and connected to the frame through the medium of the fore-and-aft link H slidably arranged in said bracket. The hand-lever H is also connected through the link H to the plurality of transverse locking bars L slidably attached to the front box-wall J and adapted to be shifted to the left and right as the hand-lever is moved backwardly and forwardly in shifting the frame H to the right and left, respectively. These bars L overlie the pr0- trading arms of the bails E and are formed in their lower edges with beveled notches, which by the shifting of the bars to the right are brought into registry with the arms of the bails to permit the rocking of the latter, and which by the shifting of the bars to the left are moved out of registry with the bail arms so as to depress the latter and hold them depressed until the bars are subsequently restored to the right.

As the foregoing parts and their mooe of operation are fully set forth in my co-pending application Serial No. 329,339, no further description seems necessary. However, in the present embodiment, the link H? is connected to the frame H and the bars L in a slightly different manner. Thus, as shown in Figs. 1 and 3, the link is formed in its bottom face with a cam groove H wherein engages a roller H carried by the arm H projecting laterally from the frame H, and in its top face it is formed with a further cam groove L wherein engages a roller L carried by the arm L projecting laterally fromv the vertical connecting plate L to which the bars L are attached. Each of the cam grooves presents an intermediate onalportion and two end parallel portions extending in the direction of movement of the link, the diagonal portions of the two grooves extending in opposite directions or at an angle to each other and one being ar ranged in advance of the other. When, therefore, the link H is drawn forwardly by the rearward movement of the hand lever H, the frame H is shifted to the right and the bars L to the left, due to the engagement of the diagonal portions of the cam grooves H and L with the rollers H and L re- .spectively. However, during the engagement of the roller L in the diagonal portion of its cam groove L the roller H is engaged in the front parallel portion of cam groove H so that the initial operation of the hand-lever does not disturb the frame H but effects only the shifting of the bars L. By the time the roller H enters the diagonal portionof its groove, the roller L has reached the rear parallel portion of its groove, and hence the continued operation of the hand lever then effects the shifting of the frame H while the bars L remain at rest in their shifted position. During the final operation of the hand-lever, the two rollers run idly along the rear parallel portions. of their respective grooves. Of course, when the link H is. pushed rearwardly by the forward movement of the hand-lever, the foregoing operation is reversed. In other words, and moregenerally'speaking, when the frame H is shifted to the right to engage the slides E with the finger keys E, the bars L are preliminarily shifted to the left soas to depress and hold depressed the forward ends of the bails E before, during and after the period of shifting of the frame; whereas, when the frame'H is shifted to the left to engage the slides .13 with the fingerstantially the same as the front and rear plates keys, the shifting of the bars to the right to release the bails does not take place until after the shifting of the frame is completed; so that, in this way, ample clearance is provided between the bails and the actuating slides during their relative adjustments, while at the same time the bails are locked and unlocked at proper periods in the ad justment of the parts. This arrangement, so far as the bars L are concerned, is subthat presented in my capending pplication above referred to, but it is particularly advantageous in connection with the following improvements which contemplate a certain amount of lost motion between the frame H and handlever H" as the latter is moved from or to either of its extreme positions.

The present invention provides means for locking the finger-keys of the keyboard against actuation except when the supportng frame is in either of its properly, ad- JllSlJGCl positions, which means are also utilized to hold the rear ends of the finger-keys depressed during the adjustments of the supporting frame. Preferably, andas herein shown, such means are operated automatically through suitable connections with the hand-lever f the arrangement being such that the finger keys are depressed, held depressed, and then released automatically b fore, during, and after each shifting movement of the supporting frame so as to provide ample clearance between the finger keys and actuating slides during their relative adjustment.

Referring now in detail vto the parts,the finger keys E, as customary, are pivoted midwaybetween their ends for vertical movement upon the transverse rods A which sustain them in rows at different levels within the supporting frame A, the keys being guided in their vertical movements by A and A fixed to the supporting frame and formed with elongated slots wherein the opposite ends of the keys are movably arranged. The front plate A which occupies an inclined position on.

the supporting frame to cooperate with the forward ends of the finger keys in the several rows is clearly illustrated in Fig. 3, its elongated slots being designated a. Slidably mounted upon ,the fixed front plate A is a locking plate C formed with elongated slots 0 through which the forward ends of the finger keys E extend, the plate C thus being practically a duplicate of the plate A It will be seen, therefore,that by adjusting the plate C backwardly and forwardly I upon the fixed plate 'A ,.the finger keys may be locked or unlocked'as desired. Thus, in the forwarder inactive position of the locking plate C, its slots 0 are in registry with the corresponding slots a of the fixed plate A (Fig. 1), so that the finger keys are free to be actuated in the usual way; but when the locking plate is in its rearward or active position, its slots are out of registry with those of the fixed plate (Figs. 2 and and hence present their lower end walls beneath and in engagement with the bottom edges of the finger keys, which are thus locked against depression or actuation. As before intimated, it is also proposed to utilize the locking means for depressing the finger keys at their rear ends so as to break their engagement with the actuating slides E E For this reason, the locking plate C is ar ranged to move rearwardly to such extent that the lower end walls of the slots 0 pass beyond a mere locking position and, by acting beneath the forward ends of the finger keys with a cam effect, raise such forward ends slightly and thereby depress the rear ends of the keys as shown in Fig. 2. It may be noted that the locking plate, in addition to the functions just mentioned, also serves when adjusted rearwardly to restore the finger keys and the connected parts to their proper positions in the event that at the time of its adjustment, one of the finger keys should be caught in its actuated condition, due for instance to the binding or sticking of its actuating slides.

In providing for the automatic adjustment of the locking plate C, it is attached at its upper end and at opposite sides to two pairs of toggle links C those of each pair being jointed together at their inner ends by a pin C and pivoted at their outer ends by pins C and C to the fixed front plate A and locking plate C, respectively, it being noted that the pins C which are secured to the fixed plate A pass through elongated slots formed in the locking plate and thus not only permit the latter to be slid forwardly and backwardly but also assist in guiding it in its sliding movements. The two pairs of toggle links are caused to work in unison by a transverse bar C connected at its opposite ends to the pins 0. According to this arrangement, the locking plate is moved backwardly to active position by straightening the toggle links and forwardly to inactive position by collapsing said links. In the embodiment illustrated, the collapse of the toggle links is effected by a spring C attached at one end to the bar C and at its opposite end to the locking plate C and tending constantly to move the bar to the right to break the toggle joints; whereas, the straightening of the toggle links is effected by means of a rocking lever C plvoted at its lower end to the fixed plate A by a pin C which passes through an elongated guiding slot in the locking plate, and slotted at its u per end to make connection with the pin 8 of the pair of toggle links situated atthe right of the keyboard. About midway between its ends, the lever C is formed with a laterally extending triangular projection (3 adapted to be engaged by the hand lever H, which is formed on its forward edge with a similar projection H that serves to extend the side face of the lever at the place of engagement. As shown, the projection (3 is provided at its apex with a roller C to track upon the extended side face of the hand lever as the latter is operated.

The action of the parts is as follows:

\Vhen the parts are at rest and in proper adjustment, the hand lever H occupies either its extreme forward or backward position, and the locking plate C is held by the spring 0 in its forward or inactive position. In this condition of the parts, the toggle links C are collapsed and position the lever C to the right with its projection C in the path of movement of the hand lever. \Vhen, therefore, the hand lever is operated to shift the supporting frame H in one direction Or the other, it engages one of the sloping edges of the projection (1 and thereby rocks the lever C to the left against the action of the spring C to straighten the toggle links and slide the locking plate rearwardly to active position, (see the full lines in Figs. 2 and 3), the rear straight edge of the hand lever engaging the front edge of the projection C when said lever is moved backwardly, and the lower inclined edge of the projection I 17 engaging the rear sloping edge of the projection (1 when the lever is moved forwardly. The locking plate is held in its active position, due to the continued engagement of the projection C with the side face of the hand lever as extended by the projection H until the lever assumes its other extreme position, when it clears the projection C and releases the spring G, which then immediately restores the locking plate to its forward or inactive position (see dotted lines in Figs. 1 and 3). It will be remembered that the hand lever H is connected to the supporting frame H with a capacity for lost motion as provided for by the parallel end portions of the cam groove H and that consequently the initial and final operations of the hand lever do not disturb the supporting frame but take place independently. It is during these independent movements of the hand lever that the foregoing operation of the locking plate is effected or controlled; That-is to say, when the hand lever is moved backwardly or forwardly to shift the frame H toward the right or left as desired, it acts first in its initial operation to slide the locking plate C rearwardly to active position before the shifting of the frame begins, and then subsequently in its independent final operation to permit the locking plate to be slid forwardly to active position after theshifting of the frame is completed, functioning in nated, It shouldbe noted that the locking.

of the finger keys in the foregoing manner.

does not interfere with the lockingof the rockmg balls as previously described; on the contrary, the present arrangement lnsuresthe proper coordination of the locking devices for these parts. In other words, through the automatic mechanism described, both the finger keys and the connecting bails are locked against actuation during theadjustment of the actuating slides, such means acting on the one hand to release the finger keys after the adjustment of the slides in eitherdirection, and on the other hand to release the bails after the adjustment of the slides in one direction only. I

It will be apparent from the foregoing description that, to effect the properadjustment of the parts, the hand lever H must be moved to its extreme forward or rearward position as required, and means are therefore provided to aid in bringing about this result. In the preferred embodiment illustrated, such means comprise a spring H attached at one end to the hand lever H at some distance above its pivot II and anchored at its other end at a point below said pivot. to a swinging arm H loosely pivoted from above, as at H, tothe bracket plate H which latter is providedwith stop pieces H arranged on opposite sides of the pivot I 12 in position to limit the swinging movements of the arm in opposite directions. In Fig. 1-, the hand lever H" is shown in its rearward position, being held in that position b the s arin H )ullin downwardl y l 2: l a l thereon from the arm H which at such time is in engagement with the rear stop piece H The spring will continue to exert its force in that direction until it is carried past dead center by the forward movement of the hand lever, when it automati cally swings the armvH into engagement with the front stop H, which thus enables the spring topull downwardly on the hand lever inits forward position. In this way,

the spring not only serves to overcome any tendency of the hand lever to occupy an improper intermediate position, but in addltion acts with considerable force to draw the lever downwardly to either of its extreme positions.

I have herein shown my invention merely in preferred form and by way of example, and as applied to a machine of the class stated, but obviously many changes and alterationsmay be made therein and in its mode ofapplication, which will still be com prised within its spirit. Generally speaking, I desire it to be understood that I do not limit myself to any specific form or embodiment except in so far as such limitations are specified in the claims.

Having thus described my invention, its construction and mode of operation, what I claimis as follows:

1. In a keyboard mechanism for typographical machines, the combination of a series of escapement actuating devices, a series of finger keys, intermediate adjustable means through which the finger keys operate the escapement actuating devices in one location or another according to the adjustment of said means, and means for preventing the actuation of the finger keys except when the parts are in properly adjusted condition. i

2. In a keyboard mechanism for typographical machines, the combination of a series of escapement actuating devices, a series of finger keys, intermediate adjust-- able means through which the finger keys operate the escapement actuating devices in one location or anotheraccording to the adjustment of said means, and automatic means for locking the finger keys against actuation except when the parts are in prep erly adjusted condition.

3. In a keyboard mechanism for typegraphical machines, the combination of a series of escapement actuating devices, a series offingerkeys, intermediate adjustable means through which the fingerkeys operate the escapement actuating devices in one loca tion or another according to the adjustment of said means, and automaticf'means for lockseries of finger keys, intermediate adjustablemeans through which the finger keys operate the escapement actuating devices in one location or another according to the adjustment of said means, locking means for the finger keys, and a common operating device for both said lockin and adustable means.

In a keyboard mechanism for typographical machines, the combination of a series of finger keys, two series of actuating slides,,a supporting frame wherein the slides are mounted and adjustable to different operative positions to connect the slides of either series with the. finger keys, and automatic means to prevent the actuation of the finger keys except when the supporting frame occupies either of its operative positions.

6. In a keyboard mechanism for typographical machines,

graphical machines, the combination of a series of finger keys. a movzfole locking device therefor, two series of actuating slides, a supporting frame wherein the slides are mounted and adjustable to connect the slides of either series with the finger keys, and automatic means for shifting the locking device to its active and inactive positions before and after the adjustment of the supporting frame, respectively, for the purpose described.

7. In a keyboard mechanism for typographical machines, the combination of a series of finger keys, a locking device therefor, two series of actuating slides, a supporting frame wherein the slides are mounted and adjustable to connect the slides of either series with the finger keys, a hand lever operatively connected to the support ing frame for affecting its adjusting movements, and means controlled by said hand lever for actuating the locking device.

8. In a keyboard mechanism for typographical machines, the combination of a series of finger keys, a locking plate formed with elongated slots through which the forward ends of the finger keys extend and movable backwardly and forwardly to shift the end walls of its slots into and out of engagement with the finger keys so as to prevent or permit the actuation of the finger keys according to the position of said locking plate, two series of actuating slides, a supporting frame wherein the slides are mounted and adjustable to connect the slides of either series with the finger keys, and automatic means for shifting the locking plate backwardly and forwardly before and after the adjustment of the supporting frame, respectively.

9. In a keyboard mechanism for typothe combination of a series of finger keys, a locking plate formed with slots through which the forward ends of the finger keys extend and movable backwardly and forwardly to shift the end walls of its slots out of and into engagement with the finger keys so as to prevent or permit the actuation of the finger keys according to the position of said locking plate. two series of actuating slides, a supporting frame wherein the slides are mounted and adjustable to connect the slides of either series with the finger keys, a hand lever opera.- tively connected to the supporting frame to effect its adjusting movements, and means controlled by the hand lever for shifting the locking plate backwardly and forwardly as required.

10. In a keyboard mechanism for typographical machines, the combination of a series of finger keys, a locking plate formed with slots through which the forward ends of the finger keys extend and movable backwardly and forwardly to shift the end walls of its slots out of and into engagement with the finger keys so as to prevent or permit the actuation of the finger keys according to the position of said locking plate, two series of actuating slides, a supporting frame wherein the slides are mounted and adjustable to connect the slides of either series with the finger keys, a hand lever operatively connected to the supporting frame to effect its adjusting movements, and means controlled by the hand lever for shifting the locking plate backwardly and forwardly as required, the said means including a toggle system connected to the locking plate, a spring tending constantly to collapse the toggle system, and a pivoted lever to extend the toggle system and arranged to be engaged and actuated by the hand lever.

11. A keyboard mechanism as specified in claim 6, characterized by the fact that the locking device therein referred to acts when in active position to hold the rear ends of the finger keys depressed so as to clear the actuating slides during the relative adjustment of the parts.

12. In a keyboard mechanism of typographical machines, the combination of a series of finger keys, two series of actuating slides, means for adjusting said parts relatively to locate the actuating slides of either series in engaging relation to the rear ends of the finger keys, and automatic means for maintaining the finger keys and actuating slides out of engagement during their relative adjustment.

13. In a keyboard mechanism of typographical machines, the combination of a series of finger keys, two series of actuating slides, means for adjusting said parts relatively to locate the actuating slides of either series in engaging relation to the rear ends of the finger keys, and automatic means for holding the rear ends of the finger keys depressed during the relative adjustment of said parts.

14. In a keyboard mechanism of typographical machines, the combination of a series of finger keys, two series of actuating slides, means for adjusting said parts relatively to locate the actuating slides of either series in engaging relation to the rear ends of the finger keys, and automatic means for holding the rear ends of the finger keys depressed during the relative adjustment of said parts, the said means being actuated to release the finger keys when such adjustment is completed.

15. In a keyboard mechanism of typographical machines, the combination of a series of finger keys, two series of actuating slides, means for adjusting said parts relatively to locate the actuating slides of either series in engaging relation to the rear ends of the finger keys, and automatic means for depressing and holding depressed the rear fore, during, and after the relative adjust of said parts, respectively.

17. In a keyboard mechanism for typo- .graphical machines, the combination of a series of pivoted vertically movable finger keys, two series of actuating slides, a supporting frame wherein the slides are mounted and adjustable longitudinally to locate the slides of either series in engaging relation to the rear ends of the finger keys, a movable locking device for holding the finger keys depressed at their rear ends, a hand lever operatively connected to the supporting frame with a capacity for lost motion in its initial operation, and means actuatedby the hand lever in its initial operation for shifting the locking device to active position.

18. In akeyboard mechanism for typographical machlnes, the combmation of a series of pivoted vertically movable finger keys, two series of actuating slides, a sup porting frame wherein the slides are mounted and adjustable longitudinally to locate the slides of either series being in engaging relation to the rear ends of the finger keys, a movable locking device for holding the finger keys depressed at their rear ends, a hand lever operatively connected to the supporting framewith a capacity for lost motion in its initial and final operations, and means controlled'by the hand lever in its initial and final operations for shifting the locking device to its active and inactive positions, respectively.

19. In a keyboard mechanism for typographical machines, the combination of a series of pivoted vertically movable finger keys, actuating slides engaged with the rear ends of the finger keys, and means cooperating with the finger keys for depressing them at their rear ends to break their e11- gageinent with the actuating slides.

20. In a keyboard mechanism for typographical machines, the combination of a series of pivoted vertically movable finger keys, actuating slides engaged with the rear ends of the finger keys, and a locking de vice cooperating with the finger keys and arranged whenmoved to active position to depress said keys at their rear ends to break their engagement wlth the actuating slides.

21. In a keyboard mechanism for typographical machines, the combination of a series of pivoted vertically movable finger keys, actuating slides engaged with the rear ends of the finger keys, and a locking plate formed with slots through which the 'forward ends of the finger keys extend, the said plate being shiftable backwardly to such extent as to cause the end walls of its slots to lift the finger keys at their forward ends and thereby depress them at their rear ends to break the engagement of said keys with the actuating slides.

22. In a keyboard mechanism for typographical machines, the combination of a series of finger keys, a series of connecting bails, two series of intermediate actuating slides, means for adjusting said slides laterally in opposite directions to vary their engagement with the finger keys and connecting bails, and automatic means for locking the finger keys and connecting bails against actuation during the adjustmeutof the intermediate slides.

In a keyboard mechanism for typographical machines, the combination of a series of finger keys, a series of connecting bails, two series of intermediate actuating slides, means for adjusting said slides laterally in opposite directions to vary their engagement with the finger keys and connecting bails, and automatic means for locking the finger keys and connecting bails against actuation during the adjustment of the intermediate slides, the said means acting to release the finger keys after the adjustment of the slides in either direction but to release the bails after the adjustment of slides in one direction only.

24. In a keyboard. mechanism for typographical machines, the combination of a series of finger keys, a series of connecting longitudinally in opposite directions to vary the engaging relation of the slides to the finger keys and connecting bails. locking' devices associated with the finger keys and connecting bails respectively, and a hand lever operatively connected to thesupport inc: frame and arranged to actuate both said locking devices. V

26. In a keyboard mechanism for typobails, two series of intermediate actuating graphical machines, the combination of means for adjusting the key connections, including a pivoted operating lever movable to difi'erent positions on opposite sides of its pivot, a swinging arm mounted independently of the lever and also movable to different positions on opposite sides of the lever pivot, a spring attached at one end to the lever and at its other end to the swinging arm and pulling on the former from the latter, and stops arranged to arrest the swinging arm in its different positions.

27. In a keyboard mechanism for typegraphical machines, the combination of means for adjusting the key connections, including a pivoted operating lever movable to different positions on opposite sides of its pivot, a spring attached at one end to said lever and serving to urge it in one direction or the other, and a shiftable element to which the spring is anchored at its opposite end, the said element acting by its shifting movements to position the anchoring point of the spring on either side of the leverpivot.

2-8. In a keyboard mechanism for typographical machines, the combination of means for adjusting the key-connections, including a pivoted operating lever movable to different positions on opposite sides of its pivot, a spring attached at one end to said lever and serving to urge it in one direction or the other, an element to which the spring is anchored at its other end and which is shittable in opposite directions to locate the anchoring point of the spring on either side of the lever-pivot, and stops arranged to arrest said element in its different shifted positions.

29. In a keyboard mechanism for typographical machines, the combination of means for adjusting the key-connections, including a pivoted operating lever movable to difl'erent positions on opposite sides of its pivot, and a spring attached at one end to the operating lever above its pivot and anchored at its opposite end at a point below said pivot and serving to urge the lever in one direction or the other, said anchoring point of the spring being so located with reference to the operating lever that the spring is carried past dead center as the operating lever is moved in opposite directions about its pivot.

30. In a keyboard mechanism for typographical machines, the combination of a series of finger keys, two sets of actuating slides, a supporting frame wherein the slides are mounted and adjustable longitudinally in opposite directions to connect the slides of either series with the finger keys, a pivoted hand lever connected to the supporting frame and movable forwardly and back wardly about its pivot, a spring attached at one end to the hand lever and serving to urge it in one direction or the other, a shiftable element to which the spring is attached at its other end, and stops arranged on opposite sides of the lever-pivot to limit the movements of the shiftable element in 0pposite directions.

In testimony whereof, I have aflixed my signature hereto.

DAVID S. KENNEDY. 

